Method and apparatus for transmitting and receiving common channel information in wireless communication system

ABSTRACT

Methods and apparatus are provided for transmission and reception of common channel information in a mobile communication system using multi-antenna-based beamforming. A number of beams to be used for transmission to a terminal is determined at a base station. The common channel information is generated corresponding to the number of beams. The common channel information is transmitted from the base station to the terminal through one of the beams.

More than one Reissue Application has been filed for U.S. Pat. No.9,948,439. This application is a Continuation Reissue of U.S.application Ser. No. 16/520,809, which is a Reissue Application of U.S.Pat. No. 9,948,439.

PRIORITY

This application claims priority under 35 U.S.C. 119(a) to applicationsfiled in the Korean Intellectual Property Office on Oct. 24, 2012 andNov. 6, 2012, and assigned Serial Nos. 10-2012-0118182 and10-2012-0125012, respectively, the contents of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a wireless mobilecommunication system and, more particularly, to initial access procedurefor a terminal to initially access a base station or a cell, and amethod and apparatus for transmitting/receiving common channelinformation therefore in a mobile communication system supporting aMultiple Input Multiple Output (MIMO) beamforming.

2. Description of the Related Art

Mobile communication systems have evolved into high-speed, high-qualitywireless packet data communication systems that provide data andmultimedia services beyond those of the early voice-oriented services.Various mobile communication standards, such as, for example, High SpeedDownlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA),Long Term Evolution (LTE), and LTE-Advanced (LTE-A) defined in 3^(rd)Generation Partnership Project (3GPP), High Rate Packet Data (HRPD)defined in 3^(rd) Generation Partnership Project-2 (3GPP2), and 802.16defined in Institute of Electrical and Electronics Engineers (IEEE),have been developed to support the high-speed, high-quality wirelesspacket data communication services.

In a wireless mobile communication system, a terminal is required toperform an initial access procedure to communicate with a base station.In the initial access procedure, the terminal receives a synchronizationsignal or Synchronization CHannel (SCH) to acquire downlinksynchronization, checks frame timing or a Cell IDentifier (ID), andreceives unique system information, base station information, or cellinformation.

Most communication standards adopt a multi-carrier multiple accesstechnique such as, for example, Orthogonal Frequency DivisionMultiplexing (Multiple Access) (OFDM (A)) using multiple subcarriers. Ina multi-carrier multiple access-based wireless mobile communicationsystem, channel estimation and measurement performance is influenced bythe number of symbols and the number of subcarriers to which thereference signal is mapped on the time-frequency resource grid. Thechannel estimation and measurement performance is also influenced by thepower that is allocated for reference signal transmission. Accordingly,by allocating more radio resources (including time, frequency, andpower), it is possible to improve the channel estimation and measurementperformance, resulting in improved received data symbol demodulation anddecoding performance and channel state measurement accuracy.

In a resource-constrained mobile communication system, however, if aradio resource is allocated for transmitting resource signals, theresource amount for data signal transmission is reduced. For thisreason, the resource amount for the reference signal transmission isdetermined by taking the system throughput into account.

Existing 3^(rd) generation mobile communications including LTE, UltraMobile Broadband (UMB), and 802.16m operate based on a multi-carriermultiple access scheme, and adopt MIMO with channel sensitive schedulingsuch as, for example, beamforming and Adaptive Modulation and Coding(AMC), to improve transmission efficiency. Furthermore, many efforts arebeing made to improve the transmission efficiency with technicalenhancements of the MIMO and beamforming techniques. One such effort toimprove transmission efficiency is Full-Dimension MIMO (FD-MIMO), whichis a technique capable of forming various beams with a few dozenantennas.

FD-MIMO is a technique for forming a narrow and long transmit beam totransmit data using a plurality of antennas so as to send the data to aterminal (or User Equipment (UE)) that far from the base station (orevolved Node B (eNB)) at a low transmit power. The FD-MIMO makes itpossible to form various types of beams depending on the number ofantennas, and also makes it possible to freely adjust the size,distance, and width of a beam according to the weights applied to theantennas, to a certain extent.

FIG. 1 is a diagram illustrating the concept of the FD-MIMO. In FIG. 1 ,an eNB 101 uses the FD-MIMO technique, and manages three cells 102, 103,and 104. The eNB 101 is required to provide UEs with a datatransmission/reception service within the coverage area of the cell 102.The eNB 101 is required to guarantee a satisfactory data transmission toUE 110 located at a cell edge 106. Using the FD-MIMO technique, it ispossible to form a narrow beam 112, 113 using several antennas and toconcentrate the power within the beam 111, so as to transmit data to theUE 110 at relatively low transmit power, as denoted by reference number111. Specifically, when it is possible to form a narrow beam with theFD-MIMO, it is also possible to reduce the transmit power fortransmitting the same data as compared to the legacy method.

Based on the low transmit power characteristic of the FD-MIMO, the eNB101 is capable of maintaining the transmit power at a low level withinthe cell 102. If the eNB is able to maintain the low transmit powerlevel, it is possible to reduce the power range supported by the poweramplifier installed in the eNB 101 and, as a consequence, significantlyreduce the cost of the power amplifier. Since the cost of the poweramplifier is an important factor in determining the eNB installationcost, the FD-MIMO is advantageous in view of the entire systemimplementation cost. Furthermore, the FD-MIMO is advantageous in thatthe reduced average power consumption makes it possible to contributethe environment-friendly Green Communication initiative.

In FIG. 1 , if the conventional method using no FD-MIMO beamforming isapplied, the data transmission coverage is restricted to the area asdenoted by reference number 105 within the area as denoted by referencenumber 102.

Even when the eNB 101 transmits data to the UE 110 located at the celledge at a relatively low transmit power, the data can be delivered tothe UE 110 with the beamforming gain. In the case of the data broadcastwithin a cell, however, it is difficult for the eNB 101 to generate thesignal covering the entire cell at the power level determined inconsideration of the FD-MIMO power gain. For example, in order togenerate the signal which UEs 110, 121, and 122 can receive within thecell 102, it is necessary to allocate a transmit power strong enough tocover the entire cell, which the eNB 101 is not able to support.

There are many signals that should be broadcast within the cell, e.g.common channel information such as an SCH necessary for acquiringsynchronization between the UE and the eNB and a Broadcast CHannel (BCH)in which the eNB broadcasts the cell information.

SUMMARY OF THE INVENTION

The present invention has been made to address at least the aboveproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the present inventionprovides a method and apparatus for transmitting distinctsynchronization signal and system information depending on thetransmission beam for facilitating initial access of the UE in the LTE-Asystem, which supports MIMO beamforming with a plurality of antennas.

Another aspect of the present invention provides an initial accessmethod that is capable of transmitting signal efficiently at lowtransmit power level in the FD-MIMO system having a few dozen or moretransmit antennas.

In accordance with an aspect of the present invention, a method isprovided for transmission of common channel information in a basestation of a mobile communication system using multi-antenna-basedbeamforming. A number of beams to be used for transmission to a terminalis determined. The common channel information is generated correspondingto the number of beams. The common channel information is transmittedthrough one of the beams.

In accordance with another aspect of the present invention, a method isprovided for receiving common channel information at a terminal in amobile communication system using multi-antenna-based beamforming. Thecommon channel information, transmitted by a base station, is received.Frame timing is acquired based on the common channel information. Asignal transmitted by the base station is processed based on the frametiming. The common channel information is generated based on a number ofbeams used by the base station, and the common channel information istransmitted through one of the beams.

In accordance with another aspect of the present invention, a basestation is provided for transmitting common channel information in amobile communication system using multi-antenna-based beamforming. Thebase station includes a transceiver configured to transmit and receivesignals to and from a terminal. The base station also includes acontroller configured to determine a number of beams to be used fortransmission to a terminal, generate the common channel informationcorresponding to the number of beams, and control the transceiver totransmit the common channel information through one of the beams.

In accordance with still another aspect of the present invention, aterminal is provided for receiving common channel information in amobile communication system using multi-antenna-based beamforming. Theterminal includes a transceiver configured to transmit and receivesignals to and from a base station. The terminal also includes acontroller configured to control receiving the common channelinformation transmitted by a base station, acquire frame timing based onthe common channel information, and process a signal transmitted by thebase station based on the frame timing. The common channel informationis generated based on a number of beams used by the base station, andthe common channel information is transmitted through one of the beams.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentinvention will be more apparent from the following detailed descriptionwhen taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating the concept of the FD-MIMO;

FIG. 2 is a flowchart illustrating an initial access procedure in thewireless communication system, according to an embodiment of the presentinvention;

FIG. 3 is a diagram illustrating a frame structure including SCH and BCHfor use in an LTE system, according to an embodiment of the presentinvention;

FIG. 4 is a diagram illustrating a multi-beam-based common channeltransmission method, according to an embodiment of the presentinvention;

FIG. 5 is a diagram illustrating a frame structure for SCH transmissionin the LTE system using the beam sweeping technique, according to anembodiment of the present invention;

FIG. 6A is a block diagram illustrating a configuration of the UE,according to an embodiment of the present disclosure;

FIG. 6B is a flowchart illustrating the operation procedure of the UE,according to an embodiment of the present invention;

FIG. 7A is a block diagram illustrating a configuration of the eNB,according to an embodiment of the present invention;

FIG. 7B is a flowchart illustrating the operation procedure of the eNB,according to an embodiment of the present invention;

FIG. 8A is a block diagram illustrating the configuration of the UE,according to an embodiment of the present invention; and

FIG. 8B is a flowchart illustrating the operation procedure of the UE,according to an embodiment of the present invention.

FIG. 9A is a block diagram illustrating a configuration of the eNBaccording to an embodiment of the present disclosure; and

FIG. 9B is a flowchart illustrating the operation procedure of the eNBaccording to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Embodiments of the present invention are described in detail withreference to the accompanying drawings. The same or similar componentsmay be designated by the same or similar reference numerals althoughthey are illustrated in different drawings. Detailed descriptions ofconstructions or processes well-known in the art may be omitted to avoidobscuring the subject matter of the present invention. Further, thefollowing terms are defined in consideration of their functionality inembodiment of the present invention, and may vary according to theintention of a user or an operator, usage, etc. Therefore, thedefinition should be made on the basis of the overall content of thepresent specification.

Although the description is directed to an OFDM-based radiocommunication system, particularly the 3GPP Evolved Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (EUTRA), itwill be understood by those skilled in the art that embodiments of thepresent invention can be applied even to other communication systemshaving a similar technical background and channel format, with a slightmodification, without departing from the spirit and scope of the presentinvention.

In an 3GPP LTE mobile communication system, the UE first performs aninitial access procedure for communication with an eNB. The initialaccess procedure includes acquiring subframe timing synchronization andframe timing synchronization with the eNB, receiving an eNB signal toacquire an ID of the eNB, acquiring system information of the eNB fromthe received signal, and configuring downlink and uplink for uplinkrandom access.

FIG. 2 is a flowchart illustrating an initial access procedure in thewireless communication system, according to an embodiment of the presentinvention.

The UE powers on, in step operation 201. The UE searches for an SCH, instep 202. The SCH includes a Primary Synchronization Signal (PSS)(hereinafter, the term ‘first synchronization signal’ is usedinterchangeably) and a Secondary Synchronization Signal (SSS)(hereinafter, the term ‘second’ synchronization signal is usedinterchangeably). The UE receives the PSS, in step 203, and acquires thesubframe time of the eNB based on the PSS. The UE receives the SSS, instep 204, and acquires the accurate frame timing and cell ID of the eNBbased on the SSS so as to check the positions of the Cell-specificReference Signal (CRS) for use in receiving downlink signal.

The UE receives a BCH, in step 205. The BCH includes a MasterInformation Block (MIB) as unique system information. The MIB includesscheduling information on a System Information Block (SIB) carrying moredetailed system information. The MIB is received through BCH, in step206. The UE acquires scheduling information on the SIB and receivesDownlink Shared Channel (DL-SCH) at the corresponding timing based onthe SIB scheduling information to acquire the SIB information, resultingin acquisition of entire system information. The SIB informationincludes operator information, cell bandwidth, neighbor cellinformation, and random access information. The UE performs randomaccess to establish a communication channel, in step 207, andcommunicates data with the eNB, in step 208.

FIG. 3 is a diagram illustrating a frame structure including SCH and BCHfor use in the current LTE system, according to an embodiment of thepresent invention.

A radio frame 301 consists of 10 subframes, and the SCH is a carrier infirst and sixth subframes 302 and 303 among the 10 subframes. The firstsubframe also carries BCH 304. Specifically, the first subframe of theradio frame 301 carries both the SCH and BCH.

Each of the SCHs 302 and 303 includes PSS and SSS. The UE receives theSCH 302 and 303 to acquire frame timing. In LTE, the SCHs 302 and 303use different codes, and each SCH consist of PSS 306 and SSS 305. ThePSS provides the UE with one of three possible physical layer identitiesand the SSS provides the UE with one of 168 cell layer identities, andthus, there are total 504 possible physical layer cell identities.

The PSS uses the same code at the first and sixth subframe 302 and 303.Accordingly, if PSS is received, the UE acquires the subframe timing soas to receive the SSS preceding right before. Meanwhile, SSS usesdifferent subcarrier mappings at the first and sixth subframe 302 and303 and thus the UE is capable of acquiring frame timing with thereceipt of only one of two SSS.

As described with reference to FIG. 2 , the UE acquires the frame timingand cell ID by receiving SCH including PSS and SSS and checks theposition of CRS to receive BCH 304 coherently. The BCH is transmittedonly at the first subframe of each radio frame as denoted by referencenumber 307 of FIG. 3 , especially at the first 4 OFDM symbols of thesecond slot of the first subframe. The UE receives the BCH over severalframes to acquire the system information and performs random access andother operation necessary for communication with the eNB.

By taking notice of the beamforming gain expected with FD-MIMO, it ispossible to reduce the transmit power level of the UE while maintainingthe cell coverage. Although the beamforming is useful for transmittingdata to one UE, it cannot be used in broadcast, e.g., a common channelsuch as SCH and BCH of LTE. This means that the reduced transmit powerlevel of FD-MIMO is not enough to broadcast the common channel, whichall of the UEs within the cell must receive.

Embodiments of the present invention proposes a method to transmit thecommon channel at different timings with several beams to cover anentire cell area.

FIG. 4 is a diagram illustrating a multi-beam-based common channeltransmission method, according to an embodiment of the presentinvention.

As shown in FIG. 4 , the cell under control of an eNB 401 is covered byfour five beams 402 to 406. Since one beam, e.g. beam 402, which isformed with the transmit power available at the eNB 401, cannot coverthe entire cell, it is difficult to allow all the UEs within the cell toreceive the common channel broadcast by the eNB 401. As shown in theembodiment of FIG. 4 , it is impossible for UEs 411 and 412 to receivethe same information carried by one beam.

Embodiments of the present invention propose a beam sweeping techniquewhich forms several distinct beams at different times. Specifically, thefirst beam 402 is formed at the first time, the second beam 403 at thesecond time, the third beam 404 at the third time, the fourth beam 405at the fourth time, and the fifth beam 405 at the fifth time.

Although FIG. 4 is directed to the case of using 5 beams for coveringthe entire cell, the number of beams may be determined or variabledepending on the real system environment. The UE 411 may receive thecommon channel through the second beam 403, and the UE 412 located atthe intersection of the third and fourth beams 404 and 405 may receivethe common channel through both the fourth and fifth beams 404 and 405.The five beams 402 to 406 may carry the same information or distinctinformation. Descriptions are made of the definitions on the SCH and BCHfor use in initial access, the method for the eNB to transmit the commonchannel, and UE operation of receiving the common channel in the case ofusing the beam sweeping technique. In embodiments of the presentinvention, the term ‘beam’ may denote a signal transmitted through abeam formed with a plurality of antenna and a beam coverage in which thesignal is receivable. Accordingly, the term ‘beam’ may be substituted bya term incorporating the above meaning.

A description is made of the FD-MIMO technique as a basis of embodimentsof the present invention.

In an embodiment of the present invention, SCH transmission is providedusing beam sweeping. As described above, the UE performs an initialaccess procedure to connect to the eNB and, in the case of using theFD-MIMO, the UE needs to use beam sweeping for transmitting downlinkcommon channel necessary for the initial access. Although thisembodiment of the present invention is directed to an LTE system framestructure and initial access procedure, the frame structure, number ofbeams, and other details may be changed without departing from the scopeof the subject matter described in embodiments of the present invention.

When using the beam sweeping technique, the common channel, such as SCH,is transmitted over all of the beams. In order to transmit the SCHarranged at two subframes of one radio frame, as shown in FIG. 3 , overseveral beams at different timings, it is necessary to use the resourcesat several different timings for SCH transmission.

FIG. 5 is a diagram illustrating a frame structure for SCH transmissionin the LTE system using the beam sweeping technique, according to anembodiment of the present invention. The SCH appearing at subframes 501and 506 are arranged as in the legacy LTE system. In the case of usingthe beam sweeping, the SCHs at the subframes 501 and 506 are transmittedover one of the beams 402 to 406 of FIG. 4 , such that it is difficultfor all the UEs within the cell to receive the SCH carried at thesubframes 501 and 506.

In an embodiment of the present invention, extra SCH is generated perbeam as shown in FIG. 5 . When using 5 beams as shown in FIG. 4 , 5beam-specific SCHs (i.e. SCH1 501 and 506, SCH2 502 and 507, SCH3 503and 508, SCH4 504 and 509, and SCH5 505 and 510) have to be generatedand transmitted on the respective beam at different timings. The SCHnumber and beam number may be mapped randomly, and the orders of SCHsand beams may match each other or mapped to each other randomly.

Although this embodiment of the present invention is directed to thecase of using the 5 beams and 5 SCHs, if the number of beams is lessthan 5, it is possible to select SCHs matching the beams in number anddetermine the SCH positions randomly or according to a predeterminedrule. As the rule of determining the SCH positions, a method ofselecting the subframes as many as the required number of SCHs from thefirst subframe may be used.

The PSS is transmitted as SCH-specific code, i.e. the code determineddifferently depending on the beam. This means that the PSS is restricteddepending on the subframe, such that the UE is capable of checking theposition of the subframe carrying the current SCH only by receiving oneSCH. In this case, if the UE receives PSS and SSS codes of the SCHdetermined based on the received beam, it is possible to determine thesubframe carrying the current SCH in the radio frame regardless of thelocation of the UE within the cell. The different PSS codes may begenerated in such a way of generating a reference PSS code and shiftingthe reference PSS code cyclically. Also, the different PSS codes may begenerated in such a way of performing scrambling on the reference PSScode.

FIGS. 6A and 6B show the operations of the UE receiving SCH in the caseof applying the beam sweeping, according to an embodiment of the presentinvention. FIG. 6A is a block diagram illustrating a configuration ofthe UE according to an embodiment of the present invention, and FIG. 6Bis a flowchart illustrating the operation procedure of the UE accordingto an embodiment of the present invention.

The UE receives SCH by means of a receiver 601, in step S601. The UEdetects the codes of the PSS and SSS included in the SCH by means of acode detector 602, in step S602. The UE acquires the frame timing withthe received code by means of a controller 603, in step S603. The UEdecodes the signal received by the receiver 601 according to the frametiming under the control of the controller 603 by means of the decoder604, in step S604.

The decoder 604 may be used for decoding the signal such as BCH andPDSCH.

FIGS. 7A and 7B show the operations of the eNB transmitting SCH in thecase of applying the beam sweeping, according to an embodiment of thepresent invention. FIG. 7A is a block diagram illustrating aconfiguration of the eNB according to an embodiment of the presentinvention, and FIG. 7B is a flowchart illustrating the operationprocedure of the eNB according to an embodiment of the presentinvention.

A SCH code generator 701 checks the number of beams to be used, in stepS701. The SCH code generator 701 generates the codes to be included inthe SCH, i.e. PSS and SSS corresponding to the number of beams, to atransmitter 703.

The transmitter 703 transmits SCH, including the code determined by acontroller 702, using the beam determined by the controller 702, at thesubframe determined by the controller 702, under control of thecontroller 702, in step S703.

In another embodiment of the present invention BCH transmission isperformed using beam sweeping. This embodiment is directed to the BCHreception according to the UE location.

In the case of using the beam steeping sweeping technique proposed inembodiments of the present invention, the SCH is transmitted at everysubframe in the LTE system as shown in FIG. 5 . BCH is mapped to thefour OFDM symbols right after the SCH in the subframe carrying the firstone of the two paired SCHs as denoted by reference number 513 of FIG. 5. Similar to SCH, if the beam sweeping is applied to BCH, the BCH istransmitted over the subframes 501 to 505.

The BCH is received at the BCH positions determined based on the frametiming acquired through SCH. The BCH carries the MIB as thecell-specific information and includes SIB scheduling information foruse in SIB as more detailed system information. For the beam sweepingwith the FD-MIMO, an embodiment of the present invention introducesbeam-specific information (hereinafter, referred to as BIB). The UEreceives the MIB through BCH transmitted by the eNB, and the MIBincludes the scheduling information on BIB. The UE receives a differentMIB depending on the beam transmitted by the eNB, so as to receive thedistinct BIB according to the received beam. If the UE receives the BCHthrough a certain beam, it acquires the system information correspondingto the received beam. Specifically, since the different information isreceived depending on the beam, the BCH is configured in the way ofreceiving different BIBs through different beams. The cell-specificinformation is transmitted in the same MIB through all the beamscarrying BCHs.

Referring to FIG. 5 , the BCH transmitted at the subframe 501 includesthe MIB corresponding to beam 1, and the MIB includes the SIB as thecell-specific information and the scheduling information for use in theBIB corresponding to beam 1 among the five beams. The BCH transmitted atthe subframe 502 includes the MIB corresponding to beam 2 and, the MBincludes the SIB as the cell-specific information and schedulinginformation for use in receiving BIB corresponding to beam 2 among thefive beams. The BCH transmitted at the subframe 503 includes the MIBcorresponding to beam 3 and, the MIB includes the SIB as thecell-specific information and scheduling information for use inreceiving BIB corresponding to beam 3 among the five beams. The BCHtransmitted at the subframe 504 includes the MIB corresponding to beam 4and, the MIB includes the SIB as the cell-specific information andscheduling information for use in receiving BIB corresponding to beam 4among the five beams. The BCH transmitted at the subframe 505 includesthe MIB corresponding to beam 5 and, the MIB includes the SIB as thecell-specific information and scheduling information for use inreceiving BIB corresponding to beam 5 among the five beams. The BIB mayinclude other information necessary for transmitting and receiving thesignals using the beam pattern, for example, uplink random accessparameter information, power control information, and TDDdownlink/uplink configuration information. Particularly, the uplinkrandom access information includes the information on the resource fortransmitting Uplink Random Access Channel (UL RACH) and, if different ULRACH resources are used for respective beams, the eNB is capable ofchecking when the UE transmits the UL RACH so as to improve thereception beamforming gain and, if the same beam is used in transmittingthe response in replay to the UL-RACH, transmission beamforming gain. Ifthe type of the beam to receive changes due to the change of the UElocation within the cell, the BIB also has to change in corresponding tothe new beam. At this time, the BIB may be transmitted to the UE throughthe BCH corresponding to the new beam or DL-SCH.

In another embodiment of the present invention, BCH is interpretedaccording to beam sweeping. This embodiment is directed to an uplinkrandom access method according to the UE location. In the firstdescribed embodiment using the beam sweeping, the beam-specific SCH istransmitted in the way of transmitting SCH per subframe, such that theUE acquires the frame timing. In the case of an LTE system, SCH istransmitted at every subframe, and the BCH is mapped to four OFDMsymbols following the SCH at the subframes carrying the first of the twopaired SCHs as denoted by reference number 513 of FIG. 5 . Like SCH, ifthe beam sweeping is used, the BCH is transmitted at the subframes 501to 505. In an embodiment of the present invention, BCH includes theinformation on a relationship between SCH and beam and UE operationdependent on the beam. Specifically, the UE that has received SCH iscapable of acquiring the information on the currently received beamthrough BCH. The UEs that receive SCH at different subframes receivedifferent beams, resulting in acquisition of different information. TheUE receives different BCH information, i.e., different MIB informationindicating the location of the BIB, interpreted according to thereceived beam as well as the beam information. The information-beamspecific information may include the other information necessary fortransmitting and receiving signal using the beam pattern such as ULrandom access parameter information, power control information, and TDDDL/UL configuration information.

FIGS. 8A and 8B illustrate operations of the UE when the BCHinterpretation method changes according to the beam in the beamsweeping-based method, according to an embodiment of the presentdisclosure. FIG. 8A is a block diagram illustrating the configuration ofthe UE, according to an embodiment of the present invention. FIG. 8B isa flowchart illustrating the operation procedure of the UE, according toan embodiment of the present invention.

The UE receives SCH by means of a receiver 801 and an SCH detector 802,in step S801. The UE reads BCH by means of a BCH decoder 803, in stepS802.

The receiver inputs the SCH information and BCH information, i.e., MIBinformation, to a controller 804, in step S803. The controller 804acquires scheduling information from BIB transmitted in the two piecesof information, in step S804, and controls the receiver 801 based on thescheduling information to receive DL-SCH at the BIB transmissionposition and acquire the BIB information at a BIB receiver 805, in stepS805.

The BIB information is input to a transmission controller 806, and thetransmission controller 806 acquires the UL random access information,particularly UL-RACH resource information, included in the BIB, in stepS806. Then the transmission controller controls a transmitter 807 basedon the UL random access information, such that the UE performs UL randomaccess on the resource indicated by UL-RACH resource informationincluded in the BIB, in step S807.

FIGS. 9A and 9B are diagrams illustrating operations of the eNB fortransmitting per-beam BCH and BIB in the case of applying the beamsweeping, according to an embodiment of the present invention. FIG. 9Ais a block diagram illustrating a configuration of the eNB according toan embodiment of the present invention, and FIG. 9B is a flowchartillustrating the operation procedure of the eNB according to anembodiment of the present invention.

A controller 901 controls an MIB generator 902 to include the schedulinginformation on the beam-specific BIB in the MIB, in step S901.

The controller 901 controls a BIB generator 903 to generate thebeam-specific BIB, in step S902, and controls a transmitter 904 totransmit the beam-specific MIB and BIB information using thecorresponding BCH and DL-SCH, in step S903. The controller 901 controlsa receiver 905 to receive UL-RACH transmitted by the UE receiving apredetermined beam.

The signal transmission/reception method of embodiments of the presentinvention is capable of efficiently performing the initial access at alow transmit power level in the FD-MIMO system having a few dozen ormore transmit antennas.

Although the internal structures of the UE and the eNB of embodiments ofthe present invention have been described with reference to theaccompanying drawings, each of the UE and the eNB may be configured witha transceiver for transmitting/receiving signal to/from the peer nodeand a controller for controlling its functions. The controller'sfunctions of each node have been described in detailed at the respectiveparts.

While the invention has been shown and described with reference tocertain embodiments thereof, it will be understood by those skilled inthe art that various changes in form and detail may be made thereinwithout departing from the spirit and scope of the invention as definedby the appended claims.

What is claimed is:
 1. A method by a base station of a mobilecommunication system using multi-antenna-based, beamforming, the methodcomprising: identifying a plurality of beams to be used fortransmission; and transmitting, to each terminal in a cell of the basestation, common channel information through each of the plurality of thebeams, wherein the common channel information is information to becommonly applied to terminals which belong to the cell of the basestation, wherein the common channel information comprises asynchronization channel including a first synchronization signal and asecond synchronization signal, and wherein the common channelinformation transmitted through each of the plurality of beams to eachterminal is included in different subframes in a frame and the firstsynchronization signal includes a beam-specific code, which is asynchronization channel-specific code determined differently dependingon the beam, such that each terminal identifies a sublime carrying thefirst synchronization signal based on the beam-specific code foracquiring frame timing.
 2. The method of claim 1, wherein the commonchannel information further comprises a broadcast channel.
 3. The methodof claim 2, wherein the broadcast channel comprises a master informationblock as cell-specific information, the master information blockcomprising scheduling information on beam-specific information includingsystem information on a certain beam, the beam-specific informationcomprising at least one of uplink random access information, powercontrol information, Time Division Duplex (TDD) downlink/uplinkconfiguration information.
 4. A method by a terminal in a mobilecommunication system using multi-antenna-based beamforming, the methodcomprising: receiving common channel information transmitted through abeam by a base station, wherein the common channel information isincluded in a certain subframe in a frame and comprises asynchronization channel including a first synchronization signal and asecond synchronization signal, the first synchronization signalincluding a beam-specific code, which is a synchronizationchannel-specific code determined differently depending on the beam,identifying the subframe carrying the first synchronization signal basedon the beam-specific code; acquiring frame timing based on a result ofthe identification of the subframe; and receiving a signal transmittedby the base station based on the frame timing, wherein the commonchannel information is transmitted through each of a plurality of beams,and the common channel information transmitted through each of theplurality of beams is included in different subframes in a frame,wherein the common channel information is information to be commonlyapplied to terminals which belong to a cell of the base station.
 5. Themethod of claim 4, wherein the common channel information furthercomprises a broadcast channel.
 6. The method of claim 5, wherein thebroadcast channel comprises a master information block as cell-specificinformation, the master information block comprising schedulinginformation on beam-specific information including system information ona certain beam, the beam-specific information comprising at least one ofuplink random access information, power control information, TimeDivision Duplex (TDD) downlink/uplink configuration information.
 7. Abase station in a mobile communication system using multi-antenna-basedbeamforming, the base station comprising: a transceiver configured totransmit and receive signals; and a controller configured to identify aplurality of beams to be used for transmission, and control thetransceiver to transmit, to each terminal in a cell of the base station,common channel information through each of the plurality of the beams,wherein the common channel information is information to be commonlyapplied to terminals which belong to the cell of the base station,wherein the common channel information comprises a synchronizationchannel including a first synchronization signal and a secondsynchronization signal, and wherein the common channel informationtransmitted through each of the plurality of beams to each terminal isincluded in different subframes in a frame and the first synchronizationsignal includes a beam-specific code, which is a synchronizationchannel-specific code determined differently depending on the beam, suchthat each terminal identifies a subframe carrying the firstsynchronization signal based on the beam-specific code for acquiringframe timing.
 8. The base station of claim 7, wherein the common channelinformation further comprises a broadcast channel.
 9. The base stationof claim 8, wherein the broadcast channel comprises a master informationblock as cell-specific information, the master information blockcomprising scheduling information on beam-specific information includingsystem information on a certain beam, the beam-specific informationcomprising at least one of uplink random access information, powercontrol information, Time Division Duplex (TDD) downlink/uplinkconfiguration information.
 10. A terminal in a mobile communicationsystem using multi-antenna-based beamforming, the terminal comprising: atransceiver configured to transmit and receive signals to and from abase station; and a controller configured to control the transceiver to:receive common channel information transmitted through a beam by a basestation, wherein the common channel information is included in a certainsubframe in a frame and comprises a synchronization channel including afirst synchronization signal and a second synchronization signal, thefirst synchronization signal including a beam-specific code, which is asynchronization channel-specific code determined differently dependingon the beam, identify the subframe carrying the first synchronizationsignal based on the beam-specific code, acquire frame timing based on aresult of the identification of the subframe, and receive a signaltransmitted by the base station based on the frame timing, wherein thecommon channel information is transmitted through each of a plurality ofbeams and the common channel information transmitted through each of theplurality of beams is included in different subframes in a frame,wherein the common channel information is information to be commonlyapplied to terminals which belong to a cell of the base station.
 11. Theterminal of claim 10, wherein the common channel information furthercomprises a broadcast channel.
 12. The terminal of claim 11, wherein thebroadcast channel comprises a master information block as cell-specificinformation, the master information block comprising schedulinginformation on beam-specific information including system information ona certain beam, the beam-specific information comprising at least one ofuplink random access information, power control information, TimeDivision Duplex (TDD) downlink/uplink configuration information.
 13. Aterminal for processing synchronization signals and system informationin a mobile communication system, the terminal comprising: atransceiver; and a processor configured to: receive, from a base stationvia the transceiver, a block including a primary synchronization signal(PSS), a secondary synchronization signal (SSS), and a broadcast channel(BCH), wherein the block is one among a set of blocks and each block inthe set of blocks is a candidate for receiving the PSS, SSS and the BCH,obtain master information in the BCH of the block, and receive, from thebase station via the transceiver, system information in a downlinkshared channel based on the master information in the BCH of the block,wherein the set of blocks are defined based on a time durationcorresponding to 5 sub-frames of 10 sub-frames within one frame, whereinthe PSS of the block is separated from the SSS and the BCH in a timedomain, wherein random access information associated with the block isincluded in the system information, wherein the block is associated witha beam-specific code and a beam of at least one beam for the set ofblocks, wherein the set of blocks are indexed in an ascending order inthe time domain, wherein a time synchronization is identified based onthe block associated with the beam-specific code, and wherein the systeminformation includes cell-specific information.
 14. The terminal ofclaim 13, wherein each block among the set of blocks is numbered and aposition of the block is predetermined.
 15. The terminal of claim 13,wherein the processor is further configured to identify a cellidentifier (ID) based on the block.
 16. The terminal of claim 13,wherein a subset of blocks transmitted from the base station isdetermined.
 17. The terminal of claim 13, wherein the random accessinformation associated with the block includes information on resourcesfor transmitting a physical random access channel.
 18. A base stationfor processing synchronization signals and system information in amobile communication system, the base station comprising: a transceiver;and a processor configured to: transmit, to a terminal via thetransceiver, a block including a primary synchronization signal (PSS), asecondary synchronization signal (SSS), and a broadcast channel (BCH),wherein the block is one among a set of blocks and each block in the setof blocks is a candidate for receiving the PSS, SSS and the BCH, andtransmit, to the terminal via the transceiver, system information in adownlink shared channel based on master information in the BCH, whereinthe set of blocks are defined based on a time duration corresponding to5 sub-frames of 10 sub-frames within one frame, wherein the PSS of theblock is separated from the SSS and the BCH in a time domain, whereinthe master information is transmitted in the BCH, wherein random accessinformation associated with the block is included in the systeminformation, wherein the block is associated with a beam-specific codeand a beam of at least one beam for the set of blocks, wherein the setof blocks are indexed in an ascending order in the time domain, whereina time synchronization is identified based on the block associated withthe beam-specific code, and wherein the system information includescell-specific information.
 19. The base station of claim 18, whereineach block among the set of blocks is numbered and a position of theblock is predetermined.
 20. The base station of claim 18, wherein a cellidentifier (ID) is identified based on the block.
 21. The base stationof claim 18, wherein the processor is further configured to determine asubset of blocks to be transmitted.
 22. The base station of claim 18,wherein the random access information associated with the block includesinformation on resources for transmitting a physical random accesschannel.
 23. A method for processing synchronization signals and systeminformation in a mobile communication system, the method comprising:receiving, from a base station, a block including a primarysynchronization signal (PSS), a secondary synchronization signal (SSS),and a broadcast channel (BCH), wherein the block is one among a set ofblocks and each block in the set of blocks is a candidate fortransmitting the PSS, SSS and the BCH; obtaining master information inthe BCH of the block; and receiving, from the base station, systeminformation in a downlink shared channel based on the master informationin the BCH of the block, wherein the set of blocks are defined based ona time duration corresponding to 5 sub-frames of 10 sub-frames withinone frame, wherein the PSS of the block is separated from the SSS andthe BCH in a time domain, wherein random access information associatedwith the block is included in the system information, wherein the blockis associated with a beam-specific code and a beam of at least one beamfor the set of blocks, wherein the set of blocks are indexed in anascending order in the time domain, wherein a time synchronization isidentified based on the block associated with the beam-specific code,and wherein the system information includes cell-specific information.24. The method of claim 23, wherein each block among the set of blocksis numbered and a position of the block is predetermined.
 25. The methodof claim 23, further comprising identifying a cell identifier (ID) basedon the block.
 26. The method of claim 23, wherein a subset of blockstransmitted from the base station is determined.
 27. The method of claim23, wherein the random access information associated with the blockincludes information on resources for transmitting a physical randomaccess channel.
 28. A method for processing synchronization signals andsystem information in a mobile communication system, the methodcomprising: transmitting, to a terminal, a block including a primarysynchronization signal (PSS), a secondary synchronization signal (SSS),and a broadcast channel (BCH), wherein the block is one among a set ofblocks and each block in the set of blocks is a candidate fortransmitting the PSS, SSS and the BCH; and transmitting, to theterminal, system information in a downlink shared channel based onmaster information in the BCH, wherein the set of blocks are definedbased on a time duration corresponding to 5 sub-frames of 10 sub-frameswithin one frame, wherein the PSS of the block is separated from the SSSand the BCH in a time domain, wherein the master information istransmitted in the BCH, wherein random access information associatedwith the block is included in the system information, wherein the blockis associated with a beam-specific code and a beam of at least one beamfor the set of blocks, wherein the set of blocks are indexed in anascending order in the time domain, wherein a time synchronization isidentified based on the block associated with the beam-specific code,and wherein the system information includes cell-specific information.29. The method of claim 28, wherein each block among the set of blocksis numbered and a position of the block is predetermined.
 30. The methodof claim 28, wherein a cell identifier (ID) is identified based on theblock.
 31. The method of claim 28, further comprising determining asubset of blocks to be transmitted.
 32. The method of claim 28, whereinthe random access information associated with the block includesinformation on resources for transmitting a physical random accesschannel.